/Engine/Source/Runtime/TypedElementFramework/Public/Elements/Framework/TypedElementList.h
Count the number of elements in this list, optionally filtering to elements that implement the given interface.
int32 CountElements ( const [TSubclassOf](API\Runtime\CoreUObject\Templates\TSubclassOf)< [UInterface](API\Runtime\CoreUObject\UObject\UInterface) > & InBaseInterfaceType ) const